Conventionally, in Patent Document 1, there is proposed a road surface condition detection device that detects a road surface condition by using a tire mount sensor mounted on the inner side of a tire, e.g., the rear surface of the tread of the tire. According to this road surface condition detection device, the road surface condition is detected by detecting a vibration transmitted to the tire using an acceleration sensor (hereinafter referred to as a G sensor) provided in the tire mount sensor and analyzing this vibration waveform.